1. Field of Invention
The present invention relates to apparatus for preventing infection from unsterile hypodermic needles or the like, and more particularly to a system for preventing needle stick or re-use of unsterile hypodermic needles or like items.
The present invention teaches in its preferred embodiment a hypodermic syringe wherein there is included a spring biased, locking pushbutton or activation tab apparatus exterior to the syringe plunger which communicates with a locking safety sheath situated at the base of the hypodermic needle prior to activation.
The safety sheath is in sliding, longitudinal communication about the needle, and is activated to its sheathing position by urging a pushbutton or activation tab on the locking pushbutton or activation tab structure in the direction of the needle, directing the sheath from about the base of the needle to over the tip of the needle. Upon communication with the tip, the safety sheath deploys a locking hatch, preventing the urging of the sheath back to the base, and rendering the needle thereafter un-reusable.
The locking apparatus of the present invention preferably operates independently of the syringe plunger, allowing the drawing and injection of fluids without interference, and is sheathed in locking position only upon the independent urging of the pushbutton or activation tab, "clicking" the sheath into a locked position.
2. Prior Art and General Background
While the prior art may teach a plurality of various devices configured to protect against needle sticks, none teach or contemplate the system as contemplated in the present invention, wherein there is provided redundant locking as a "fail-safe" apparatus.
Since the early 1980's it has been recognized that instruments which come into contact with human tissue fluids can comprise biohazards, particularly when those instruments come into contact with HIV, hepatitis, and other tissue infected with contagion.
Further, it has been recognized that the sharing and re-usage of disposable needles has transmitted HIV among intravenous drug users.
Consequently, there has evolved a plethora of re-designs of existing hypodermic syringes and related devices, wherein there has been incorporated features to prevent infection and, in the case of disposable systems, reuse.
Often, the distraction surrounding a medical emergency or like situation may result in used syringes not being identified as being particularly contaminated. This could result in the re-use of the syringe by a medical professional and potential contamination resulting therefrom.
Additionally, if the syringe is not properly disposed of an addict may thereafter utilize it to administer illegal drugs to himself and others, spreading the virus, bacteria, disease, or anything else which may be present on the point and shaft of the hollow metal needle.
It is for this reason that an easily operated, consistent and tamper proof, syringe needle capping system is needed, so that the utilized needle may be automatically capped immediately after use, even in the heat of a medical emergency, without distraction and in a consistent and unfailing manner.
A list of prior patents which may be of interest is presented below:
______________________________________ U.S. Pat. No. PATENTEE(S) ISSUE DATE ______________________________________ 4,702,738 4,725,267 Vaillancourt 2/16/88 4,790,828 Dombrowski et al 12/13/88 4,804,371 Vaillancourt 2/14/89 4,813,940 Parry 3/21/89 4,838,863 Allard et al 6/13/89 4,486,796 Carrell et al 7/11/89 4,850,968 Romano 7/25/89 4,861,338 Mathiesen et al 8/29/89 4,863,434 Bayless 9/5/89 4,887,998 Martin et al 12/19/89 4,894,055 Sudnak 1/16/90 4,908,023 Yuen 3/13/90 4,921,486 DeChellis et al 5/01/90 4,932,940 Walker et al 6/12/90 4,936,830 Verlier 6/26/90 4,955,868 Klein 9/11/90 4,966,593 Lennox 10/30/90 4,986,818 4,994,046 5,026,353 Bartman 6/25/91 ______________________________________
U.S. Pat. No. 4,702,738 addresses the problem of inadvertent pricks, but the safety is easily manipulated once the system is locked by manipulating the spring force, easily overcoming it by hand. Further, the difficulties in performing the basic functions of using the syringe are increased by the need for holding the shield handle during injection.
U.S. Pat. No. 4,725,267 addresses the problem of inadvertent pricks by covering the point of the needle, but activating it requires the operator to work in the area of the point of the needle, increasing the potential contamination risk simply to cover the needle. Further, the cover could be forced back exposing the needle, potentially causing a prick.
U.S. Pat. No. 4,790,828, issued in 1988, teaches a "Self-capping Needle Assembly", wherein in FIGS. 1, 2 and 6, there is contemplated a locking needle capping assembly utilizing biased blockage means, albeit distinguishable in operation and design from that contemplated by the present invention.
Namely, the activation system which must be manually lifted in the '828 system is more cumbersome to operate with one hand and could actually encourage needle stick, versus the present invention, which contemplates a push-button system wherein there is a lesser chance for needle stick during the activation of the capping mechanism.
U.S. Pat. No. 4,804,371 addresses the problem of inadvertent pricks by covering the needle, but can be pushed out of the way if one desires to overcome the system, thereby preventing re-use. U.S. Pat. No. 4,994,046, issued in 1991, discloses a "Needle Guard for Syringe", wherein there is taught a side mounted apparatus for controlling the shield means, albeit completely distinguishable in form and operation from the present invention.
U.S. Pat. No. 4,863,434, issued in 1989 describes an "automatic needle sheath for disposable syringe" wherein a needle capping assembly is disclosed (note FIG. "A") offering biased blocking members to cover the needle. However, the '434 patent fails to contemplate an efficient, inexpensive, and safe system as taught in the present invention.
U.S. Pat. No. 4,936,830 addresses the problem of inadvertent pricks and reuse, but works only on pre-filled syringes.
U.S. Pat. No. 4,986,818, issued Jan. 22, 1991, and U.S. Pat. No. 4,990,141, issued Feb. 5, 1991, also teach single use syringes utilizing a type of safety capping assembly again distinguishable from the present invention, but nonetheless pertinent with respect to the generalized concept of a single use syringe system.
Finally, U.S. Pat. No. 5,026,353 issued Jun. 25, 1991 teaches a "multi-chamber safety syringe", contemplating a rather bulky, complicated, and expensive system for preventing needle stick, wherein there is taught essentially the incorporation of dual spring biased reciprocating pistons on opposing sides of the syringe to force forward a capping assembly.
As taught, the device of the '353 patent may not only be considered impractical, but also does not teach a safe locking mechanism over the needle. In fact, as the capping system is apparently contemplated, the cap is not locked in place over the needle and may in fact slide out of the needle cap, if the cap is urged towards the base of the needle, exposing it. Therefore, if one were to bump or sit atop the cap, the cap could slide back, sticking and potentially infecting that person.